Known internal combustion engines include valves that control the flow of intake air into a combustion chamber and the flow of exhaust gases out of the combustion chamber. A valve assembly, part of which is positioned within a rocker box of the engine, includes a spring configured to bias the valve to a closed position. A valve stem seal is provided on a stem of the valve to prevent oil within the rocker box from entering the combustion chamber and conversely, to prevent exhaust gases from entering the rocker box. Typically, valve springs and valve stem seals are subject to conduction heating from the heat of combustion absorbed into a cylinder head. High temperatures and repeated temperature cycling (between periods of operation and periods of non-operation) of the valve springs and valve stem seals can lead to decreased closing force on the valve, valve stem seal degradation, and increased oil consumption by the engine.